The invention relates to a video circuit including a conversion unit which has for its object to convert, under the control of a clock signal, an analog signal or a digital signal, respectively, whilst preserving the information contained therein, into a digital or an analog signal, respectively; and separation means for producing a galvanic separation from ground in the video circuit.
Such a video circuit is described in an article "Aufbereitung von Fernsehsignalen fur 140Mbit/s-Verbindungen" by F. Hornung and F. Schalamon, published in Telcom Report 10 1987, special: "Multiplex- und Leitungseinrichtungen".
Such a video circuit is frequently used to preprocess a video signal applied thereto either as an analog signal or as a digital signal to give it a shape appropriate for further processing to or from a transmission circuit.
To avoid hum in the video circuit, it is customary to provide a galvanic separation from ground, in order to create "floating" video inputs.
To that end, in accordance with the above prior art a separation transformer is arranged between a video signal source, for example a video camera, and the input of a video circuit. Such a proposed solution has the drawback that such a ground separation transformer must be capable of transmitting the signal at base-band level. Such a requirement is an impediment to a cost-effective solution of the ground separation problem.
The invention has for its object to obviate the above drawback.